The software giant announced this morning that it had filed a suit against Comet Group PLC, accusing the group of manufacturing counterfeit discs at a factory in Hampshire and selling them through its UK retail outlets. Comet has 248 stores across the UK. A spokesperson for Microsoft was unable to say where the suit has been filed.

The allegedly counterfeit recovery discs were then sold to customers who had bought desktops and laptops running Windows, Microsoft said.

Microsoft's associate general counsel for worldwide anti-piracy and anti-counterfeiting David Finn called Comet's actions "unfair to customers" in this morning's statement.

In an official statement, Comet told The Reg it had sought legal advice from "leading counsel" to "support its view that the production of recovery discs did not infringe Microsoft’s intellectual property."

Responding specifically to Finn, Comet said it "firmly believes that it acted in the very best interests of its customers" and that punters had been "adversely affected by the decision to stop supplying recovery discs".

"Accordingly Comet is satisfied that it has a good defence to the claim and will defend its position vigorously," the retailer said.

Comet made an operating loss for the six months to October of €6.4m (£5.3m). Owner Kesa Electricals group is selling Comet to private equity shop OpCapita for £2 with the sweetener of a £50m capital injection from Kesa. The deal is expected to close next month. ®